Abstract: An in-line concurrent diagnostic analyzer for laser beams. An aperature mor splits the initial laser beam into two beams. The reflected portion of the initial beam follows path 1. Along path 1, an aliquot of the path 1 beam is reflected into a time history sensor. The majority of the path 1 beam ignites a plasma to mark beam arrival time at the target. The aperatured beam strikes and heats a calorimeter mirror, which records the energy of the incident beam. About 99 percent of the aperatured beam then passes to a specially designed (thin, with a short diffusion time) mirror attached to thermocouples to record the energy profile of the beam. The beam is reflected by the special mirror onto the target. A Third sensor detects any breakdown at the target surface.